Amir BashirE11-15 PG 11

Table of contentsTube Rupture

◦ Line of action…………………………………………..

◦ Why it occurs…………………………………………..

◦ Stages………………………………………………….....

◦ How to avoid…………………………………………..

Battery Limits:◦ Usage in industries………………………………..◦ Pictorial representation…………………………

Personal protective equipment

◦ Types of Hazard………………………………….

Air Sox

Tube Rupture

When a tube breaks down due to conditions that are considered haphazard, such a definition is known as tube rupture. It can be defined in two ways

a) The tube failure is a sharp break in one tube.

b) The tube failure is assumed to occur at the back side of the tube sheet.

A Picture is always worth a thousand words!

Line of action

Heat Exchanger

Why it arises?

High and Low pressure zones contribute

Significantly to tube rupture!

1. When there is a significant pressure differencebetween the shell and tube side of the heatexchanger

2. When the high pressure zone exceeds a pressure of1000psig

3. If the high pressure side contains a liquid or a vapor,that may vaporize and can result in the subsequentvaporization of the liquid on low pressure zone.

Stages of tube rupture

2/3rd rule

It states that:

◦ If pressure on the low pressure side is greater than or equal to 2/3rd of the pressure on the high pressure side, there is negligible danger of tube rupture

If we apply 2/3rd rule on this pipe, then it is NOT dangerous when it comes to tube rupture

10/13 rule

It states that:◦ If pressure on the low pressure side is greater than

or equal to 10/13 on the high pressure side, then the risk of tube rupture can be ignored

If we apply 10/13 rule on this pipe, then it is NOT dangerous when it comes to tube rupture

Hydro-static testThis test is basically used to minimize the tube rupture characteristic of the pipe.

It is carried out before the tube or pipe is used in a setting i.e. that of heat exchanger.

It is used to test pipelines, gas cylinders, boilers for strength and leaks

1. The tube is filled with a incompressible liquid i.e. water

2. One side is closed while water is filled through other side

3. Pressure is increased above the design pressure

4. After Pressure is achieved, supply valve is closed and Pressure monitored

5. If there is a decrease in Pressure, it will indicate some sort of leakage

6. By doing this, we can determine leakage, strength and location of leakage

Steps1. Analysis of the heat exchanger should be carried out

considering the tube vibration, tube wall thickness.

2. Usage of PSV’s

3. The design pressure of the heat exchanger should be increased if it is operated at high pressure in order to mitigate tube rupture

4. If possible, it is best to keep the low pressure fluid on the shell side.

5. Usage of a vapor pocket on low pressure side

Battery LimitAreas which are specifically designated to different departments in a refinery or a chemical plant is known as battery limit.

This is more often than not, a physical boundary, that is used to differentiate the process units from the supporting equipment

Battery limits help to define the role of an engineer by making him know that which task he is expected to do, in which area of the industry

Pictorial representation

Personal Protective equipment

Personal protective equipment's or PPE’s, are the devices thatare used for safety not only in the industries, but everywhere.

Since the introduction of safety standards i.e. OHSAS, PPE’s havebecome an integral part of modern industries.

Their basic purpose is to reduce the hazards to which, theemployees will be exposed in engineering works

Need to protect!

Types of Hazards

Regulations:

1. Properly assessed before usage to make sure it is suitable for the purpose

2. Maintained and stored properly

3. Provided with instructions on how to use it safely

4. Used correctly by employees

Limitations:

1. discrepancy between theoretical and actual levels of protection provided exists

2. only effective if correctly selected, fitted, used, and cared for, and the individual is trained.

3. the choice of PPE may compromise mobility, visibility, communication

Air SoxAir Sox, or in common language known as wind sox, are used to determine the direction of air flow.

It is designed to indicate wind direction and wind speed.

Wind-speed is indicated by the wind-sox’ angle relative to the mounting pole.

They are typically used at gas plants and airports

Ok with the wind direction, but howcan it indicate the wind speed?

Here it is!According to the Canadian transport standards, a 15KN wind will fully extend the wind-sox.

A 10KN wind, will extend the wind sox to about 5* below the horizontal.

And a 6KN wind, will extend it to 30* below the horizontal.